There is a need in the engine industry for greater control over the combustion process. The goal of such control is to provide for adequate power output while using fuel efficiently. In addition, unwanted emissions must be minimized, such emissions include: noxious by-products of the combustion process as well as noise. A reduction of noise emissions is particularly critical for compression ignition engines.
A way to achieve at least a portion of the control necessary to meet the afore-stated goals is by switching from cam operated engine valves to camless technology. Camless technology, at least in theory, allows direct control over dwell, the amount of valve opening (partial or full), the aggressiveness of the valve opening and closing, and other engine valve related parameters. Such control is highly advantageous in meeting the afore-mentioned goals.
Design of viable camless technology has not proven an easy task. One great concern in the viability of camless technology is the ability to control engine valve motion. Actuators that are coupled to the engine valve and that require substitution for typical cam engine valve lifts typically have required a sensor and a sophisticated feedback control system in order to control the engine valve motion. This results from the fact, that being directly coupled to the valve, requires such camless technology to account for valve lash arising from a variety of sources. Such systems have been experimented with by FEV, Siemens, Ford, Sturman, and others. Such systems demand large computer processors and the sheer size and cost of the control boards necessary for such processors have made them prohibitive both with respect to the space required proximate the engine valve, the cost of the processors themselves, and compromises to the design of internal combustion engines. The physical space proximate the engine valves for affecting engine valve motion is extremely limited, for this reason, the devices associated with camless technology need to be quite small as well as being reliable, fast, and accurate, while at the same time limiting the cost of such components.